1. Field of the Invention
The present invention is directed to a system and method for transferring radio frequency energy from a radio frequency power supply to a slab type gas laser.
2. Prior Art
Slab type gas lasers, such as carbon dioxide (CO2) lasers, are used for industrial purposes and have developed into lightweight and economical devices for performing various industrial cutting, engraving and similar operations. Metal plates or slabs are utilized as electrodes having a large contact area and forming a chamber between the plates. Typically, cooling is provided within the slabs, such as a water cooling system, to prevent overheating of the laser.
Such a laser typically has a radio frequency power amplifier (RFPA) to provide radio frequency (RF) power to the slabs of the laser. The RF energy creates plasma in the chamber formed between the slabs. Typically, the impedance of the plasma between the slabs and the impedance of the RFPA are not the same. The difference in impedance between the plasma and the RFPA causes a significant loss of power transfer from the RFPA to the laser. This also increases accumulation of heat not only in a laser but in the entire RF circuit system of the laser.
To reduce the problem of energy loss and maximize the power transfer in RF circuits, several systems have been introduced to perform impedance matching between the RFPA and the electrodes of a laser. Combinations of transformers, resistors, inductors, capacitors and transmission lines have been typically used for impedance matching in RF circuits including slab type gas lasers. Although such systems may prevent some of the problems related to power loss and overheating, the systems have not been satisfactory and still have several drawbacks. For example, typical impedance matching systems are placed remotely from laser assemblies and thus require transmission lines or cables to connect the impedance matching systems to the laser assemblies, which cause additional power loss and overheating. Moreover, such systems employ high voltage capacitors, which are expensive and require additional cooling; thereby adding unwanted cost to the manufacturing of lasers.
It can be seen that a new and improved system for matching impedance between a RFPA and a slab type gas laser is required. Such a system should provide a simple and inexpensive adjustable configuration for impedance matching to reduce energy loss and maximize power transfer between a RFPA and electrodes of a slab type gas laser. Moreover, such a system should allow efficient dissipation of heat generated in the system so as to eliminate the necessity of a cooling device in the system. The present invention addresses these as well as other problems associated with impedance matching systems for gas slab lasers.